2021-05-24 一些抗菌劑帶有令人擔憂的一線希望
Some antibacterials come with worrisome silver lining一些抗菌劑帶有令人擔憂的一線希望
By JULIE DEARDORFF and TRIBUNE REPORTER
FEB 16, 2014 AT 2:00 AM
Silver has long been known for its ability to kill some of the nasty microbes that can make people sick. In hospitals, it's used to help burn victims, to combat germs on catheters and even to wipe out dangerous "superbugs" that have grown resistant to traditional antibiotics.
長期以來，白銀以其殺死某些可能使人患病的令人討厭的微生物的能力而聞名。在醫院中，它被用來幫助燒傷患者，與導管上的細菌作鬥爭，甚至消滅對傳統抗生素產生抗藥性的危險“超級細菌”。
Now, capitalizing on consumers' fear of germs, companies are adding tiny, powerful silver particles to cutting boards, underwear, yoga mats, running shirts, socks and an expanding array of other "antibacterial" goods.
現在，公司利用消費者對細菌的恐懼，在切菜板，內衣，瑜伽墊，運動衫，襪子和其他“抗菌”商品中添加了微小而有力的銀顆粒。
Such products are made possible by recent advances in technology that allow manufacturers to create nano-sized silver and incorporate it into various materials. (A nanometer is one-billionth of a meter; a human hair is about 80,000 to 100,000 nanometers wide.)
此類產品通過最近的技術進步而成為可能，該技術允許製造商製造納米尺寸的銀並將其結合到各種材料中。 （納米是十億分之一米；人的頭髮大約是80,000至100,000納米。）
But some scientists and environmental watchdog groups say putting nanosilver to widespread use may pose risks, as no one knows how chronic exposure to the particles may affect human health or the ecosystem in the long run.
但是一些科學家和環境監管機構表示，將納米銀廣泛使用可能會帶來風險，因為沒人知道長期暴露於顆粒中會長期影響人類健康或生態系統。
They also worry that silver may lose its power to fight infections if bacteria become more resistant, a phenomenon already seen with other antibiotic drugs and with triclosan, an ingredient added to antibacterial soaps, cosmetics and other commercial goods.
他們還擔心，如果細菌變得更有抵抗力，銀可能會失去抵抗感染的能力，這種現像已經在其他抗生素藥物和三氯生中出現，三氯生是抗菌肥皂，化妝品和其他商品中添加的成分。
"Some humans are quite frightened of bacteria, and the tendency to overuse silver is likely," said Samuel Luoma, an emeritus researcher with the U.S. Geological Survey and the author of "Silver Nanotechnologies and the Environment," a report published by the Pew Project on Emerging Nanotechnologies.
美國地質調查局名譽研究員，《銀納米技術與環境》一書的作者塞繆爾·洛馬說：“有些人對細菌相當恐懼，並且有可能過度使用銀。”關於新興的納米技術。
"What concerns me is the explosion of products which we don't know are effective and that are not necessary," Luoma said. "It's important to prove it's worth taking the risk before we put it in the environment."
Luoma說：“令我擔心的是，我們不知道有效和不必要的產品爆炸。” “重要的是證明在將風險投入環境之前值得承擔風險。”
The U.S. Environmental Protection Agency recently began requiring manufacturers of nanosilver to register their products, saying the particles could pose different risks than conventional silver. But critics, including the Natural Resources Defense Council, say the agency's process is flawed because it allows the products to be sold commercially several years before safety studies are completed.
美國環境保護署最近開始要求納米銀的製造商對其產品進行註冊，稱納米銀顆粒與傳統銀相比可能帶來不同的風險。但是包括自然資源保護委員會在內的批評人士說，該機構的程序存在缺陷，因為它允許產品在安全研究完成之前幾年就可以商業化銷售。
Consumers, meanwhile, often can't tell whether products contain nano-sized silver because nanomaterials aren't required to be labeled.
同時，消費者通常無法分辨產品是否包含納米尺寸的銀，因為不需要在納米材料上貼標籤。
"The presence of nanotechnology in consumer products has gone underground," said Emma Fauss, who in 2008 compiled an inventory of commercial nanotechnology products for the Pew project. "Manufacturers shy away from labeling things in their products unless it's trendy. There's a perception that if it's labeled, it could be dangerous."
Emma Fauss說：“消費類產品中存在納米技術，這已經變成地下現象了。”他在2008年為Pew項目編制了商業納米技術產品清單。 “製造商迴避在產品中貼標籤，除非它是時髦的。人們普遍認為，如果貼上標籤，可能會很危險。”
Silver kills germs when it oxidizes and releases silver ions, which are lethal to bacteria and yeast. Ancient civilizations used the metal to treat open wounds, and American pioneers tossed silver coins into water storage barrels to keep water fresh.
銀氧化並釋放出對細菌和酵母具有致命性的銀離子時會殺死細菌。古代文明使用這種金屬來治療傷口，美國先驅者將銀幣扔入儲水桶中以保持水的新鮮。
Nanoparticles of silver, which can occur naturally, are more powerful than bigger particles because their large surface area relative to their mass increases the number of ions released.
天然存在的銀納米粒子比大粒子更強大，因為相對於其質量而言，大的表面積增加了釋放的離子數量。
The silver industry says concerns about nanosilver are unfounded, pointing to silver's history as an effective antibiotic agent and noting that most applications use very small quantities.
白銀行業表示，對納米銀的擔憂是沒有根據的，它指出了白銀作為一種有效抗生素的歷史，並指出大多數應用使用的銀量很少。
It also says nano-sized silver isn't new and has been in continual use for more than a century. Nanoscale silver products have been safely used in swimming pools and drinking water purification since the 1970s, said Rosalind Volpe, executive director of the Silver Nanotechnology Working Group.
它還說，納米銀並不是新的，並且已經連續使用了一個多世紀。銀納米技術工作組執行董事羅莎琳德·沃爾普說，自1970年代以來，納米級銀產品已被安全地用於游泳池和飲用水淨化。
"It's the most sustainable and by now the most researched and safest biocide technology on the market," said Carlo Centonze, CEO of the Swiss company HeiQ, which produces nano-sized silver, primarily for use in medical products.
瑞士公司HeiQ的首席執行官Carlo Centonze說：“這是市場上最可持續的，目前是研究最安全的殺生物技術。”該公司生產的納米級銀主要用於醫療產品。
Some manufacturers also argue that treating textiles with silver nanoparticles benefits the environment by reducing the need for washing, allowing cleaning at lower temperatures and making the products more durable.
一些製造商還爭辯說，用銀納米顆粒處理紡織品可減少洗滌需求，允許在較低溫度下進行清潔並使產品更耐用，從而對環境有利。
In general, experts agree that humans can safely tolerate fairly high doses of silver. What's new is that over the past decade nanoparticles have been manipulated and put in places where silver has never been before.
通常，專家們認為人類可以安全地忍受相當高劑量的銀。最新消息是，在過去的十年中，納米粒子已被操縱並放置在從未有過的白銀中。
Some scientists and environmental health groups fear that the very properties that make these particles useful — their vanishingly small size and high surface area — may have unintended consequences once they get into the human body and the environment.
一些科學家和環境衛生組織擔心，一旦使這些顆粒進入人體和環境，其特有的性質-逐漸消失的小尺寸和高表面積-可能會產生意想不到的後果。
Both animal studies and computer models have found that nanoparticles, including nanosilver, can spread throughout the body into organs and tissues.
動物研究和計算機模型均發現，包括納米銀在內的納米顆粒可以在整個人體中擴散到器官和組織中。
"Nanoparticles are little bundles of pure metal that can dissolve within the body if taken up as a particle," said Luoma.
Luoma說：“納米顆粒是一小束純金屬，如果被吸收成顆粒，它們就會溶解在體內。”
"To me," he added, "the big risk is to ingest or breathe nanosilver when we don't know for sure if there's a unique risk in this form."
他補充說：“對我來說，最大的風險是當我們不確定是否以這種形式存在獨特的風險時，攝入或呼吸納米銀。”
Like other germ-killers, including antibiotics, nanosilver also could upset the delicate balance of bacteria inside the digestive tract, said Marina Quadros, associate director of the Virginia Tech Center for Sustainable Nanotechnology. "Under the right conditions, silver nanoparticles are very effective in killing bacteria, both the good and the bad," she said.
弗吉尼亞納米技術可持續發展技術中心副主任瑪麗娜·誇德羅斯說，與其他殺菌劑（包括抗生素）一樣，納米銀也可能破壞消化道內細菌的微妙平衡。她說：“在適當的條件下，納米銀顆粒可以很好地殺死細菌，無論是好是壞。”
Beyond the possible impact of nanosilver on human health, environmental concerns loom large.
除了納米銀對人類健康的可能影響外，對環境的關注也越來越大。
"There is clear evidence that silver, and in particular nanosilver, is toxic to aquatic and terrestrial organisms" and to cells from mammals in laboratory research, the EPA stated in a 2010 report.
EPA在2010年的一份報告中指出：“有明顯證據表明，銀，尤其是納米銀，對水生和陸地生物以及哺乳動物的細胞具有毒性。”
Potential sources of nanosilver pollution include landfills, wastewater treatment plants and industrial facilities. Several lab studies also have found that nanosilver can leach out of products when washed.
納米銀污染的潛在來源包括垃圾填埋場，廢水處理廠和工業設施。幾項實驗室研究還發現，納米銀在洗滌後會從產品中浸出。
"If we start using tons of silver nanoparticles and a lot more are going down the drain, then we might start to have an effect we haven't seen in the past," said Amy Pruden, a professor of civil and environmental engineering at Virginia Tech who is investigating whether silver nanoparticles in waste streams can stimulate antibiotic resistance in microbes.
弗吉尼亞州土木與環境工程學教授艾米·普魯登（Amy Pruden）表示：“如果我們開始使用大量的納米銀顆粒，而越來越多的納米顆粒正在消耗盡，那麼我們可能會開始產生我們以前從未見過的效果。”正在研究廢物流中的銀納米顆粒是否可以刺激微生物中的抗生素抗性的技術人員。
Some studies have found that nanosilver in wastewater tends to be transformed into silver sulfide, a much less toxic substance, said Mark Wiesner, director of the Center for the Environmental Implications of Technology at Duke University.
杜克大學技術環境影響研究中心主任馬克·維斯納說，一些研究發現，廢水中的納米銀往往會轉化為毒性較小的硫化銀。
Researchers there also found that the vast majority of nanosilver that enters a wastewater treatment center is removed from the water as it sticks to bacteria that feed off organic matter.
那裡的研究人員還發現，進入廢水處理中心的絕大多數納米銀由於粘附在以有機物為食的細菌上而被從水中去除。
But these bacteria, Pruden said, eventually settle out to form biosolids, or "sludge," that is applied as fertilizer to agricultural land. Nanosilver in the sludge could affect the soil bacteria responsible for cycling nitrogen and carbon, she said.
但是，普魯登說，這些細菌最終會沉澱下來，形成生物固體或“污泥”，將其作為肥料施用於農田。她說，污泥中的納米銀可能會影響導致氮和碳循環的土壤細菌。
Pesticides, which include chemicals that kill bacteria, must be registered with the EPA before they can be sold or distributed. But until recently, the agency did not consider nanosilver to be different from regular silver. That allowed a variety of nanosilver products to enter the market based on the toxicity data for conventional silver.
農藥（包括殺死細菌的化學藥品）必須在EPA進行註冊，然後才能出售或分發。但是直到最近，該機構才認為納米銀與普通銀沒有什麼不同。根據傳統銀的毒性數據，這使得各種納米銀產品可以進入市場。
The EPA now reviews nano-sized silver separately, recognizing that nano-sized particles have different characteristics and may have different effects on human and environmental health. Since 2011, the agency has "conditionally approved" two pesticide products containing nanosilver as the active ingredient.
EPA現在已經分別審查了納米級的銀，並認識到納米級的顆粒具有不同的特性，並且可能對人類和環境健康產生不同的影響。自2011年以來，該機構已“有條件地批准”了兩種以納米銀為有效成分的農藥產品。
Environmental health organizations complain that the conditional approval process allows products to be marketed several years before all the safety studies have been submitted, potentially putting consumers at risk.
環境衛生組織抱怨說，有條件的批准程序允許產品在所有安全研究報告提交之前幾年就進入市場，從而可能使消費者面臨風險。
Last year, the Government Accountability Office reported that the EPA couldn't reliably or systematically track how many products had been conditionally registered or whether the safety studies were submitted. In its response, the EPA said it was working to improve its oversight, including designing an automated data system.
去年，政府問責辦公室報告說，EPA無法可靠或系統地跟踪有條件註冊的產品數量或是否提交了安全性研究。 EPA在回應中說，它正在努力改善其監督，包括設計一個自動化數據系統。
For consumers, the safety picture on nanosilver is murky to say the least. Products launched before the change in EPA rules remain on the market, and little information is available on how much silver a product contains and what size it might be.
對於消費者而言，至少可以說，納米銀上的安全性圖片模糊不清。在EPA規則變更之前推出的產品仍在市場上，並且幾乎沒有關於產品包含多少銀以及可能有多少尺寸的信息。
When the European Commission tried to investigate the safety, health and environmental effects of nanosilver, it had difficulty reaching any conclusions.
當歐盟委員會試圖調查納米銀的安全，健康和環境影響時，很難得出任何結論。
"A specific human risk assessment for silver nanoparticles is not feasible as information on possible long-term effects are lacking," its report stated.
報告指出：“由於缺乏有關可能的長期影響的信息，因此無法對銀納米顆粒進行具體的人類風險評估。”
Until such data are collected, some argue that nanosilver shouldn't be used in consumer products, in part to preserve silver's ability to fight infections.
在收集到此類數據之前，有人認為納米銀不應該用於消費產品，部分原因是為了保持銀的抗感染能力。
Germany's risk management agency cited that reason in arguing that silver should not be used as an antimicrobial ingredient on a large scale, with the exception of medical applications.
德國風險管理機構援引該理由，認為除醫療用途外，不應將銀大規模用作抗菌成分。
"Silver was and continues to be a valuable tool," said Andrew Maynard, director of the University of Michigan Risk Center. "There is a real fear that if we are indiscriminate with use, we could accelerate resistance."
密西根大學風險中心主任安德魯·梅納德（Andrew Maynard）表示：“銀曾經是而且仍然是一種有價值的工具。” “人們確實擔心，如果我們不加區分地使用，我們可能會加速抵抗。”
But Maynard also said people may have taken the assumption of harm too far, in the absence of more concrete evidence. Using nanosilver in a product may make sense if it serves a medical purpose and proves effective, he said.
但是梅納德還說，在沒有更具體的證據的情況下，人們可能已經把傷害的假設推得太遠了。他說，如果將納米銀用於醫療目的並證明有效，則在產品中使用納米銀可能是有意義的。
"Rather than a marketing ploy, it should be something that will benefit people," Maynard said. "We've survived for many years without having antimicrobial shirts and tools."
梅納德說：“這應該是使人們受益的東西，而不是行銷手段。” “我們在沒有抗菌襯衫和工具的情況下生存了很多年。”
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